补充代码低频和高频的提取

clc;
clear all;
p=imread('12.jpg');
q=imread('21.jpg');
p=double(p)/256;
q=double(q)/256;
imshow(p);
figure;
imshow(q);
figure;
[c1,s1]=wavedec2(p,4,'sym4');
[c2,s2]=wavedec2(q,4,'sym4');
length=length(c1);
hecheng=zeros(1,s1(1,1)*s1(1,2));  %提取的是低频部分
A1=zeros(1,s1(2,1)*s1(2,2));  %用于提取第二层的水平高频图
hecheng(1:s1(1,1)*s1(1,2))=c1(1:s1(1,1)*s1(1,2));  %开始复制值,这里需要理解c的结构
A1=c1(s1(1,1)*s1(1,2)+1:s1(1,1)*s1(1,2)+s1(2,1)*s1(2,2));  %复制值
temp=reshape(A1,s1(2,1),s1(2,2));  %将一维的转化成二维的
image(temp);   %显示高频图
figure;
hecheng=reshape(hecheng,s1(1,1),s1(1,2));
imshow(hecheng,[]);  %显示低频图，注意和image的区别
%image(hecheng);